Two companies involved in the production of a Birmingham musical in which 15 audience members dressed as nuns were injured when the stage collapsed have each been fined #14,000.
Theatre operator Clear Channel Entertainment was also ordered to pay #12,111 costs and producers Sing-ALong Productions #9,747.
They admitted breaches of Health & Safety regulations by failing to ensure the safety of audience members at the Sound of Music singalong show at Birmingham's Alexandra Theatre in 2003.
Judge William Everard, at Birmingham Crown Court, said it had been a "terrifying" experience for those involved as well as their friends and families although mercifully no one was killed.
He said the accident was "wholly avoidable" and there had been inadequate measures put in place warning members of the public about standing on an orchestra pit cover which gave way.
He said it was an accident that could have been prevented by simply someone using a microphone to warn people of the danger.
The judge said, though, he accepted that the accident had not been the result of any cost-cutting or deliberate breach of Health and Safety regulations.
Barry Berlin, prosecuting, said the incident happened on September 30 2003.
He said about a quarter of an hour into the opening, members of the audience dressed as nuns were called on to the stage for a fancy dress competition.
About 40 to 50 people then came on, unaware that the orchestra pit cover at the front was not load bearing.
He said there were no ushers and that one of those invited described things getting tighter and tighter as more people squeezed on.
"The orchestra pit cover collapsed and some members of the public tumbled seven and a half feet into the black pit beneath on to unforgiving carpeted concrete.
"Some were struck with falling debris and others were struck with falling bodies."
Mr Berlin said injuries suffered by the victims ranged from heavy bruising to multiple fractures and that one woman sustained a severely broken leg which had left her ten per cent disabled.
Mark Turner QC, for Clear Channel, claimed the accident happened because the compere for whatever reason, did not know what she was doing.
He said there had been a breakdown in communication within Sing-A-Long and that the fancy dress party was organised contrary to every one that had been performed in the past, members of the audience being invited on the stage before ushers were ready.
James Martin-Jenkins QC, for Sing-A-Long, said it had since taken measures to ensure that a similar accident could never happen again.
Clear Channel Entertainment leased the theatre and the show was produced by Sing-Along Productions.